The HMG-CoA inhibitor, simvastatin, triggers in vitro anti-tumour effect and decreases IgM secretion in Waldenstrom macroglobulinaemia

Waldenström Macroglobulinemia: Mechanisms of Disease Progression and Current Therapies

Waldenström macroglobulinemia is an indolent, B-cell lymphoma without a known cure. The bone marrow microenvironment and cytokines both play key roles in Waldenström macroglobulinemia (WM) tumor progression. Only one FDA-approved drug exists for the treatment of WM, Ibrutinib, but treatment plans involve a variety of drugs and inhibitors. This review explores avenues of tumor progression and targeted drug therapy that have been investigated in WM and related B-cell lymphomas.

Associations between statin use and risk of non-Hodgkin lymphomas by subtype

Non-Hodgkin lymphomas (NHL) are a group of cancers with highly heterogeneous biology and clinical features. Statins are increasingly prescribed to prevent cardiovascular diseases. Early evidence shows a preventive effect of statins for some cancers, but their effect on NHL risk is unclear. We conducted a population-based nested case-control study involving 5,541 NHL cases and 27,315 controls matched for gender, age, place of residence and length of period of available prescription drug data. We assessed the use of statins prior to diagnosis (excluding the 12 months prior to the index date). We used conditional logistic regression models to estimate odds ratio (OR) and 95% confidence interval (CI) for use of any statin, adjusting for medical conditions, number of family physician visits for 5 years prior to index date, healthcare utilization, income and use of other medications. Over one-quarter of cases and controls were prescribed statins. Ever-use of any statin was associated with lower risk of Total NHL (OR = 0.82, 95% CI 0.76-0.89) and of certain subtypes including diffuse large B-cell lymphomas (DLBCL, OR = 0.77, 95% CI 0.65-0.92), plasma cell neoplasms (PCN, OR = 0.76, 95% CI 0.63-0.91) and other B-cell NHL (0.75, 0.59-0.95). Analysis by statin type suggested that the association was limited to high potency statin and lipophilic statin users. No clear duration or dose-response relationships were observed. Our findings provide evidence that statin use can reduce the risk of DLBCL and plasma cell lymphomas, but not other NHL types. Further studies are warranted to verify these associations and to examine the biological mechanisms.

Would Lipophilic Statin Therapy as a Prognostic Factor Improve Survival in Patients With Uterine Cervical Cancer?

Objectives

In vitro studies showed that lipophilic statins inhibit cell growth, adhesion, and invasion and induce apoptosis in cancer cell lines. In uterine cervical cancer, several important factors including age, stage, anemia, lymphovascular invasion, lymph node metastases, and parametrial spread were known to significantly predict survival. We investigated whether statin therapy as a prognostic factor would significantly predict survival in cervical cancer.

Methods

Patients with stages IB to IV cervical cancer who received radical hysterectomy and/or para-aortic lymph node dissection were included. The statin-use group was identified as patients who were continuously prescribed with lipophilic statins from prediagnostic period of the cancer.

Results

The baseline characteristics of both statin-use group and control group were comparable. During a median follow-up of 36.6 months, progression-free survival and overall survival of the statin-use group were significantly higher than the control group (P < 0.001 and P = 0.004, respectively). In multivariate analysis, the statin-use group had an independent prognostic significance compared with other prognostic factors (progression-free survival: hazards ratio = 0.062, 95% confidence interval = 0.008–0.517, P = 0.010; overall survival: hazards ratio = 0.098, 95% confidence interval = 0.041–0.459, P = 0.032).

Conclusions

In the present study, continuous lipophilic statin therapy from the prediagnostic period of uterine cervical cancer could reflect favorable outcome, independently.

Recent Advances in the Development of Mammalian Geranylgeranyl Diphosphate Synthase Inhibitors

The enzyme geranylgeranyl diphosphate synthase (GGDPS) catalyzes the synthesis of the 20-carbon isoprenoid geranylgeranyl diphosphate (GGPP). GGPP is the isoprenoid donor for protein geranylgeranylation reactions catalyzed by the enzymes geranylgeranyl transferase (GGTase) I and II. Inhibitors of GGDPS result in diminution of protein geranylgeranylation through depletion of cellular GGPP levels, and there has been interest in GGDPS inhibitors as potential anti-cancer agents. Here we discuss recent advances in the development of GGDPS inhibitors, including insights gained by structure-function relationships, and review the preclinical data that support the continued development of this novel class of drugs.

A phase II Bayesian sequential clinical trial in advanced Waldenström macroglobulinemia patients treated with bortezomib: interest of addition of dexamethasone

In patients with advanced Waldenström macroglobulinemia (WM), overall response rate (ORR) and median progression-free survival (PFS) achieved with bortezomib alone and bortezomib rituximab combination were 27-85% and 7.9 months, and 81% and 16.4 months, respectively. We checked the role of dexamethasone in combination with bortezomib by enrolling in a phase II trial 34 patients with relapsed/refractory WM. Bortezomib (1.3 mg/m² IV D1, 4, 8, and 11 every 21 days) was used for six cycles. In non-responding patients, dexamethasone (20 mg daily for two days) was added to each infusion after the second cycle. After two cycles, the Bayes estimated ORR was 43.2 (95% Credible Interval: 28.0-59.1%) using the informative prior. Two-year survival rate was 84.0% and the median PFS 15.3 months without difference between patients treated with or without dexamethasone. We conclude that dexamethasone must be associated to bortezomib-based regimen.

Associations between statin use and non-Hodgkin lymphoma (NHL) risk and survival: a meta-analysis

Evidence on the effect of statin use on non-Hodgkin lymphoma (NHL) is not clear. We conducted a systematic review and meta-analysis to examine the associations between statin use and NHL risk and survival. We searched multiple literature sources up to October 2014 and identified 10 studies on the risk of diagnosis with NHL and 9 studies on survival. Random effects model was used to calculate pooled odds ratio (PORs) for risk and pooled hazard ratio (PHR) for survival. Heterogeneity among studies was examined using the Tau-squared and the I-squared (I² ) tests. Statin use was associated with reduced risk for total NHL (POR = 0.82, 95% CI 0.69-0.99). Among statin users, there was a lower incidence risk for marginal zone lymphoma (POR = 0.54, 95% CI 0.31-0.94), but this was not observed for other types of NHL. However, statin use did not affect overall survival (PHR = 1.02, 95% CI 0.99-1.06) or event-free survival (PHR = 0.99, 95% CI 0.87-1.12) in diffuse large B-cell lymphoma. There is suggestive epidemiological evidence that statins decrease the risk of NHL, but they do not influence survival in NHL patients. Copyright © 2015 John Wiley & Sons, Ltd.

HMG-CoA reductase inhibitors as adjuvant treatment for hematologic malignancies: what is the current evidence?

Statins have been shown to possess properties that go beyond their lipid-lowering effects. These agents act on the mevalonate pathway and inhibit synthesis of cholesterol, geranylgeranyl pyrophosphate, and farnesyl pyrophosphate, which are necessary for posttranslational modification of the Rho, Rac, and Ras superfamily of proteins. Early phase studies have demonstrated that this modulation of cellular signaling can ultimately exert pro-apoptotic, anti-angiogenic, and immunomodulatory effects, and might even restore chemosensitivity in several hematologic cancers. Nonetheless, these promising preclinical results have not yet migrated from the bench to the bedside as their effectiveness as adjuvant agents in hematologic malignancies is currently uncertain. In the present review, we summarize the existing evidence stemming from preclinical and clinical studies pertaining to the use of statins as adjuvant therapies in hematologic malignancies, and discuss the new insights gained from the ongoing translational research.

Autophagy contributes to apoptosis in A20 and EL4 lymphoma cells treated with fluvastatin

Convincing evidence indicates that statins stimulate apoptotic cell death in several types of proliferating tumor cells in a cholesterol-lowering-independent manner. However, the relationship between apoptosis and autophagy in lymphoma cells exposed to statins remains unclear. The objective of this study was to elucidate the potential involvement of autophagy in fluvastatin-induced cell death of lymphoma cells. We found that fluvastatin treatment enhanced the activation of pro-apoptotic members such as caspase-3 and Bax, but suppressed the activation of anti-apoptotic molecule Bcl-2 in lymphoma cells including A20 and EL4 cells. The process was accompanied by increases in numbers of annexin V alone or annexin V/PI double positive cells. Furthermore, both autophagosomes and increases in levels of LC3-II were also observed in fluvastatin-treated lymphoma cells. However, apoptosis in fluvastatin-treated lymphoma cells could be blocked by the addition of 3-methyladenine (3-MA), the specific inhibitor of autophagy. Fluvastatin-induced activation of caspase-3, DNA fragmentation, and activation of LC3-II were blocked by metabolic products of the HMG-CoA reductase reaction, such as mevalonate, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). These results suggest that autophagy contributes to fluvastatin-induced apoptosis in lymphoma cells, and that these regulating processes require inhibition of metabolic products of the HMG-CoA reductase reaction including mevalonate, FPP and GGPP.

HMG-CoA reductase inhibitors induce apoptosis of lymphoma cells by promoting ROS generation and regulating Akt, Erk and p38 signals via suppression of mevalonate pathway

Statins, the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are widely used cholesterol-lowering drugs. Convincing evidence indicates that statins stimulate apoptotic cell death in several types of proliferating tumor cells in a cholesterol-lowering-independent manner. The objective here was to elucidate the molecular mechanism by which statins induce lymphoma cells death. Statins (atorvastatin, fluvastatin and simvastatin) treatment enhanced the DNA fragmentation and the activation of proapoptotic members such as caspase-3, PARP and Bax, but suppressed the activation of anti-apoptotic molecule Bcl-2 in lymphoma cells including A20 and EL4 cells, which was accompanied by inhibition of cell survival. Both increase in levels of reactive oxygen species (ROS) and activation of p38 MAPK and decrease in mitochondrial membrane potential and activation of Akt and Erk pathways were observed in statin-treated lymphoma cells. Statin-induced cytotoxic effects, DNA fragmentation and changes of activation of caspase-3, Akt, Erk and p38 were blocked by antioxidant (N-acetylcysteine) and metabolic products of the HMG-CoA reductase reaction, such as mevalonate, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). These results suggests that HMG-CoA reductase inhibitors induce lymphoma cells apoptosis by increasing intracellular ROS generation and p38 activation and suppressing activation of Akt and Erk pathways, through inhibition of metabolic products of the HMG-CoA reductase reaction including mevalonate, FPP and GGPP.

Isoprenoid biosynthetic pathway inhibition disrupts monoclonal protein secretion and induces the unfolded protein response pathway in multiple myeloma cells

Myeloma is characterized by the overproduction and secretion of monoclonal protein. Inhibitors of the isoprenoid biosynthetic pathway (IBP) have pleiotropic effects in myeloma cells. To investigate whether IBP inhibition interferes with monoclonal protein secretion, human myeloma cells were treated with specific inhibitors of the IBP or prenyltransferases. These studies demonstrate that agents that inhibit Rab geranylgeranylation disrupt light chain trafficking, lead to accumulation of light chain in the endoplasmic reticulum, activate the unfolded protein response pathway and induce apoptosis. These studies provide a novel mechanism of action for IBP inhibitors and suggest that further exploration of Rab-targeted agents in myeloma is warranted.

Statins can modulate effectiveness of antitumor therapeutic modalities

Despite significant, frequently very strong, antiproliferative and tumoricidal effects of statins demonstrated in vitro, their antitumor effects in animal models are modest, and their efficacy in clinical trials has not been proven. As such, statins seem unlikely to be ever regarded as antitumor agents. However, statins are regularly taken by many elderly cancer patients for the prevention of cardiovascular events. Owing to their pleiotropic effects in normal and tumor cells, statins interact in various ways with many antitumor treatment modalities, either potentiating or diminishing their effectiveness. Elucidation of these interactions might affect the choice of treatment to be planned in cancer patients as some combinations might be contraindicated, whereas others might elicit potentiated antitumor effects but at a cost of increased general toxicity. Some other combinations might induce either comparable or even stronger antitumor effects, but with a beneficial concomitant reduction of specific side effects. Most of the studies reviewed in this article have been carried in vitro or in experimental tumor models, but clinical relevance of the findings is also discussed.

Statin use and prognosis in patients with diffuse large B-cell lymphoma and follicular lymphoma in the rituximab era

PURPOSE

Statins have antilymphoma properties but have also been shown to inhibit the binding of rituximab to the CD20 antigen, resulting in reduced antitumor activity of rituximab in vitro. The clinical impact of statin use on the outcome of lymphoma patients treated with a rituximab-containing regimen is unknown.

PATIENTS AND METHODS

Consecutive patients with newly diagnosed, diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) were enrolled onto a registry and observed prospectively. The impact of statin use on patients' outcomes was analyzed.

RESULTS

Two hundred twenty-eight patients with DLBCL and 293 patients with FL were enrolled from September 2002 through June 2007; 21% of patients with DLBCL and 19% of patients with FL were on statins at diagnosis, and 20% and 17% remained on statins during lymphoma treatment, respectively. All patients with DLBCL and 39% of patients with FL received initial therapy containing rituximab. The median follow-up time was 47 months (range, 13 to 80 months). Statin use had no impact on the overall response rate (P = .67), overall survival (P = .76), or event-free survival (EFS) in patients with DLBCL (hazard ratio [HR] = 0.85; 95% CI, 0.43 to 1.68). Statin use at diagnosis was associated with improved EFS in patients with FL (HR = 0.45; 95% CI, 0.26 to 0.77), including subgroups treated with rituximab or a rituximab-containing regimen (HR = 0.38; 95% CI, 0.14 to 1.07) and patients who were observed only (HR = 0.38; 95% CI, 0.17 to 0.84).

CONCLUSION

The concurrent use of statins during the treatment of patients with DLBCL and FL in the rituximab era did not adversely affect outcome. The apparent benefit of statin therapy on FL outcome requires further studies.

Update on therapeutic options in Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell disorder characterized primarily by bone marrow infiltration with lymphoplasmacytic cells (LPCs), along with demonstration of an IgM monoclonal gammopathy in the blood. WM remains incurable, with 5-6 yr median overall survival for patients with symptomatic WM. The main therapeutic options include alkylating agents, nucleoside analogues, and rituximab, either in monotherapy or in combination. Studies involving combination chemotherapy are ongoing, and preliminary results are encouraging. However, there are several limitations to these approaches. The complete response rate is low and the treatment free survival are short in many patients, no specific agent or regimen has been shown to be superior to another, and no treatment has been specifically approved for WM. As such, novel therapeutic agents are needed for the treatment of WM. In ongoing efforts, we and others have sought to exploit advances made in the understanding of the biology of WM so as to develop new targeted therapeutics for this malignancy. These efforts have led to the development of proteasome inhibitors, of them bortezomib, several Akt/mTor inhibitors, such as perifosine and Rad001, and immunomodulatory agents such as thalidomide and lenalidomide. Many agents and monoclonal antibodies are currently being tested in clinical trials and seem promising. This report provides an update of the current preclinical studies and clinical efforts for the development of novel agents in the treatment of WM.